VSD AI Input Overrun Limit Setup
To set up a EMHEATER VSD with a Pressure Transmitter to provide protection against over pressure, the pressure transmitter can be set up as a STOP trigger to stop the VSD once a certain pressure value has been reached. To do this, please see the below wiring and parameter settings.
Wiring
- Connect GND and COM
- Connect Pressure Transmitter to 24V and AI1
- Set AI1 jumper to I
*Please use shielded cable to prevent electromagnetic interference by other appliances on the analog signal sent to the VSD. For EMC Mitigation: 1) Allow for at least 20cm distance between communication cables and motor wires. 2) Do not use the same cable tray. 3) Insert wires in metal pipes if possible.
To set AI1 Min/Max Values
The AI1 Min/Max Parameter settings ranges between 0V and 10V (in this example the output will not be Volt but rather mA, but the parameter will still be set as if it is a ‘Volt’ value). Since the output from the Pressure Transmitter is 4-20mA, the max of 20mA will correspond to 10V and the minimum of 4mA will correspond to 2V (10V/20mA = 0.5 and then 0.5 * 4mA = 2V). Therefore, the ‘Volt’ equivalent output of the Pressure Transmitter will be 2V to 10V. Thus set:
- b5-07= 2.00 (AI1 Minimum input value)
- b5-09 = 10.00 (AI1 Maximum input value)
To set the STOP function for the Input Limit
- b7-00 = 38 (VDI1 function selection = Normally Open input of external fault)
- b7-11 = 34 (AI1 input limit exceeded – will give Error15 if AI1 Input limit is exceeded – Press ‘Reset’ (STOP) to clear the Error)
To set the Input Limit (max Bar before STOP)
- b5-05=0.00 (AI1 input voltage lower limit of protection – will also STOP when input value = 0V, which is not applicable in this scenario as the Minimum is 2V)
- b5-06 = Value based on Pressure Limit (AI1 input voltage upper limit of protection – see calculation further down)
To set the Top Line of the Keypad Display to show the AI1 Output (‘Volt’ equivalent output of the Pressure Transmitter)
- b9-11 = 9 (U0-09 = AI1 voltage)
Calculating b5-06 (based on Pressure Limit)
Since the Output = (b5-07) 2 to (b5-09) 10, this means the value Range = 8 (10 – 2). So, a 50% output from the Pressure Transmitter will provide a value of 6V, derived as 8 (Range) * 50% + 2 (b5-07: the minimum input value). Example:
To set the max pressure of a 25 Bar Transmitter = 15 Bar, use 15 / 25 = 0.6 and calculate b5-06 as 8 (Range) * 0.6 + 2 = 6.8 (Thus, set b5-06 = 6.8)
The below chart shows different ‘Voltage’ outputs and Bar (Pressure) readings for 2 different Pressure Transmitters (a 10 Bar and 25 Bar Transmitter).
For other similar scenarios please also see:
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using the VSD Parameters to set a Fixed Target Pressure, please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using an external analog signal (such as a PLC) to modify the target pressure (Variable Target Pressure), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter to provide Constant Water Pressure using an external Multi-Stage Switch to modify the target pressure (Target Pressure Selector), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter for Frequency Control using a PID (Manage Water Outflow), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD with a Pressure Transmitter for Frequency Control using a PID (Manage Water Inflow), please see the relevant FAQ entry HERE.
For additional Protection Features, please also see:
– To set up a EMHEATER VSD End of Curve Parameters (PID Signal Loss Protection), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD Low Current Protection (Dry Run Protection), please see the relevant FAQ entry HERE.
– To set up a EMHEATER VSD Restart (Delayed) after Low Current Protection Condition Occurred (Dry Run Protection Reset), please see the relevant FAQ entry HERE.
