Application notes

	Note on open-circuit recognition from firmware 04 The open-circuit recognition runs acyclically in the background. The open-circuit recognition for the potentiometer wiper takes place every 3 cycles, if the value 10k (0) is entered in all 0x80n0:1C objects (on all channels). In this case the open-circuit recognition is particularly fast. If a >20 kOhm potentiometer is nevertheless connected to one of the channels, a broken wire message may occur, even if no broken wire is present. Therefore, the nearest suitable value that matches the connected potentiometer should be set in 0x80n0:1C. The open-circuit recognition for the wiper is slower, if at least for one channel a value >10k ( > 0) has been entered.

Diagnostic options

The diagnostic functions of the terminal can be set via the CoE object 0x8047:11.
The settings apply to all channels together:

Application notes 2: — Set Value Dialog, diagnostic options

Sensor Monitoring: Wiper wire break detection
Load Monitoring: Monitoring of the potentiometer supply lines
Supply monitoring: Monitoring of the 24 V supply via the power contacts, potentiometer overload/short circuit

It is recommended to use the full diagnostic scope if possible. If the terminal detects an error, Value=0 and Error=1 are reported.

In some cases it can happen that potentiometer wipers lose contact with the contact surface during movement, especially at higher speeds or increasing aging. In this case the wiper wire break detection can be switched off to avoid false alarms. Wiper wire break detection is performed by cyclic voltage pulses. The pulses can be measured from the outside (if the wiper is not grounded), but are not included in the measurement result of the channel.

Further characteristics

Feature	Explanation
Potentiometer	The potentiometers connected to channels 1 - 5 do not have to be of the same type or resistance value.
Power dissipation	Significant portions of power are converted into heat in the connected potentiometers. Due to the terminal feed of typically 10 V, approx. 0.3 W are converted in a 300 Ω potentiometer.
Diagnostics	The Error LED or the status word indicates broken wire in one of the three potentiometer supply cables short-circuit on the potentiometer supply (shunt) A shunt between the wiper conductor and one end of the potentiometer feed cannot be recognized. See "Note on open-circuit recognition from firmware 04"
Compensation of supply cable resistances	In the case of very long cable lengths with small cross-sections the line resistances A and C can limit the measuring range. This error can be corrected with the "user calibration" function: To do this, activate the IIR 8 filter and the "Enable user calibration" function. Set the potentiometer to the lower limit and enter the input value in "User calibration offset". Then set the potentiometer to the upper limit and calculate the "User calibration gain": Y = 32768/X*16384.

Error Codes

Error	Underrange	Overrange	Data invalid	TxPDO State	Sync Error	Error description	Remedy
1	1					Measurement is below range	Reduce the input level, change the gain (filter settings)
1		1				Measuring range exceeded	Reduce the input level, change the gain (filter settings)
1						General measuring error	e.g. broken wire or short circuit
					1	Synchronization error	Master jitter too high, DC switched off
			1			Internal data error	Check data transmission
				1		Internal data error	Check data transmission