AC2520 - Electronic module IFM - Free user manual and instructions

Product type	AS-i electronic module
Model	AC2520
Brand	IFM
Power supply	Via AS-i bus (24 V)
Pt100 measuring range	-200 °C to 850 °C
Resolution	0.1 °C
Conversion time (4 channels)	480 ms
Total transmission time (4 values)	Approx. 620 ms
Maximum number of modules per AS-i network	31
AS-i profile	S-7.3.E
Sensor connection	M12 connectors (2-wire or 4-wire)
Adjustable parameters	50/60 Hz filter, enable device fault per channel, 2/4-wire selection
LED display	4 yellow LEDs (analog channels), 1 green AS-i PWR LED, 1 red FAULT LED
Dimensions (approx.)	50 x 50 x 30 mm
Weight (approx.)	100 g
Maintenance	Clean with a dry, lint-free cloth
Safety	Follow the instructions in the manual; disconnect power before maintenance
Repairability	Repair by manufacturer only

Frequently Asked Questions - AC2520 IFM

How to connect a 2-wire Pt100 sensor to the AC2520 module?

Connect the 2-wire sensor to pins Pin 1 (S +) and Pin 2 (Al +) for measurement. Pins 3 and 4 are not used. Make sure parameter bit P3 is set to 1 (2-wire mode).

How to connect a 4-wire Pt100 sensor?

Connect the 4-wire sensor to pins: Pin 1 (S +), Pin 2 (Al +), Pin 3 (S -) and Pin 4 (Al -). Pin 5 is the functional ground. Set parameter bit P3 to 0 (4-wire mode).

How to address the AS-i AC2520 module?

You can address the module by mounting it on an addressing unit (AC1144) and assigning a free address between 1 and 31. For bases with addressing connector (AC5010), use the addressing cable E70213.

What do the LEDs on the AC2520 module mean?

The yellow LEDs AI1 to AI4 indicate the status of analog signals: on within measuring range, flashing outside. The green AS-i PWR LED indicates AS-i voltage present. The red FAULT LED indicates a communication error (steady) or a device fault (flashing).

How to set the 50/60 Hz filter on the AC2520 module?

Parameter bit P0 selects the filter: P0=1 for 50 Hz (recommended in Europe), P0=0 for 60 Hz.

How to enable the device fault message on a specific channel?

Use parameter bits P1 and P2. Refer to the table in the manual to configure which channels (1 to 4) trigger the device fault. The combinations are defined by P1 and P2.

What is the measuring range of the AC2520 module?

The measuring range for Pt100 sensors is -200 °C to 850 °C. Outside this range, the LEDs flash or turn off according to short-circuit or wire break thresholds.

What is the total transmission time for 4 temperature values?

The conversion time is 480 ms for 4 channels, and transmission via AS-i takes about 140 ms, for a total of approximately 620 ms in ideal conditions.

What to do if the FAULT LED is steady on?

A steady FAULT LED indicates an AS-i communication error, for example a slave address of 0. Check the module address and connection to the AS-i network.

What is the difference between the AC2520 and AC2570 models?

The AC2570 model is a variant with stainless steel screws and a Viton gasket, providing better resistance to corrosive environments. The electrical characteristics are identical.

USER MANUAL AC2520 IFM

Function and features

The AS-i slave converts analogue signals (temperature values) into digital values and transfers them to the host.

The data transfer is asynchronous according to the AS-i profile S-7.3 and the AS-i specification V2.1.

• Sensor supply from AS-i
• Conversion of measured values for 4 channels: 480 ms
• Resolution 0.1^ C
• Measuring range -200...850 °C
  AS-i profile S-7.3.E
• The Pt100 sensors are connected via M12 connection cables.
• Connection of 2-wire / 4-wire sensors possible
  Maximum number of modules per AS-i system: 31
• special features AC2570: stainless steel screws, Viton sealing

Installation/Addressing

When you use module lower parts without addressing socket (AC5000 or AC5001) first address the module by placing it onto an addressing unit (AC1144) and assign a free address between 1 and 31.

When you use module lower parts with an addressing socket (AC5010) the modules can be addressed with the addressing adapter E70213 later on.

Mount the module onto the wired module lower part of the AS-i network, tightening torque 0.8 Nm.

As an alternative FC/FC-E lower parts with earthing lead (AC5020...AC5023) can be used to increase the noise immunity.

Electrical connection

The analogue module is connected to the AS-Interface via the standardised EMS [(supply from AS-i) (also in this case the Pt100 sensors are supplied from the AS-i voltage)].

For all the following wiring diagrams the indicated pin connection refers to the analogue module.

Connection of a 2-wire Pt100 element to the AS-i module

Analogue modul

Pin 1: S +

Pin 2: Al +

Pin 3: S -

Pin 4: Al -

Pin 5: screen (functional earth)

2-wire Pt100

Analogue modul

Pin 1: S +
Pin 2: Al +
Pin 3: S -
Pin 4: Al -
Pin 5: screen (functional earth)

4-wire Pt100

4-wire Pt100 sensors supply more exact results than 2-wire sensors provided that the wire resistance is the same.

The changeover between 2- and 4-wire sensors is made via the parameter bit P3.

Important notes regarding Pt100 measurements:

In the Pt100 measurement principle, very low currents flow in the measuring electronics. It must be ensured that additional resistance (cables, contact and transition resistance, loose contacts, etc.) is avoided in the measuring circuit.

Only this way is a precise measurement, for which these modules are designed, possible.

In detail:

A 4-wire measurement always has to be preferred over a 2-wire measurement. In 2-wire measurement all transition and connection resistances add up and may massively falsify the measurement result.

Therefore a 2-wire measurement is not recommended!

High-quality plugs should be used for the AS-i AC2520 Pt100 module. Prewired and potted plugs with gold-plated contacts should be preferred.

Parameter setting of the analogue modules

Parameter bit/ Designation	Description		Comments
P0 filter	1 50 Hz filter in the A/D converter active		The 50 Hz filter applies to the whole of Europe
	0 60 Hz filter in the A/D converter active
P1, P2 periphery fault	Parameter bit		Periphery fault can be triggered by
	P1 P2		1	2	3	4
	0	0	on	off	off	off
	0	1	on	on	off	off
	1	0	on	on	on	off
	1	1	on	on	on	on
P3 selection Pt100 elements	1	2-wire mode
	0	4-wire mode

Activation of the periphery fault message of the channels 1 to 4

According to the table above the parameter bits P1 and P2 are used to define which measuring channels can trigger a periphery fault message. But irrespective of the defined parameters all 4 channels are always transferred via the AS-Interface.

It is necessary to connect at least one Pt100 sensor before switching on the AS-i slave to start the A/D converter, otherwise the LEDs I1 to I4 flash at a frequency of about 5 Hz.

Operation

Check the safe functioning of the unit. Display by LEDs:

• LEDs yellow Al1 ... Al4 on: analogue signal in the measu

ring range

flashing: analogue signal outside the measuring range

• LED green AS-i PWR on: AS-i voltage is applied

• LED rot FAULT on: AS-i communication error

e.g. slave address 0

flashing: periphery fault *

• periphery fault

A periphery fault is indicated if at least one of the signals AI1, AI2, AI3 or AI4 is outside the measuring range or if nothing is connected to at least one analogue channel.

Measuring range of the Pt100 module

For the measuring ranges, the LED states and their meaning please see the following table:

Range -200...850 °C	Units dec.	Units hex.	LED AI1...AI4 analogue	Meaning
< -219.4 °C	32767	7FFF	flashes	short circuit
-219.4 °C... -200.1 °C	-2194 ... -2001	F76E ... F82F on below nominal		range
-200°C... +850 °C	-2000 ... 8500	F830 ... 2134	on	nominal range
850.1 °C... 883.6 °C	8501 ... 8836	2135 ... 2090	on	above nominal range
>883.6 °C	32767	7FFF	off	wire break

Transmission time of the analogue values

The transmission time of the analogue values depends on the conversion time of the analogue signals into digital signals in the AS-i module and on the transmission time via the AS-Interface.

The conversion time for 4 Pt100 signals is 480~ms .

The transmission time of the 4 16-bit values via the AS-Interface ideally is 7 AS-i cycles per value. For a cycle time of 5 ms per AS-i cycle this results in a transmission time of 4 × 7 × 5 ms = 140 ms via the AS-Interface.

Thus the total transmission time for 4 temperature values ideally is 480ms (conversion time) +140ms (transmission time) = 620ms .