Basic Documentation

Page 6 of 9 Siemens Industry, Inc.
Document No. A6V10431169
2. A custom PID preset for HVAC and fluid systems, allows a pressure or flow signal to be connected to
the VFD, using the microprocessor in the VFD for the closed loop control. The VFD shall have 250
mA of 24 Vdc auxiliary power and be capable of loop powering a transmitter supplied by others. The
PID setpoint shall be adjustable from the VFD keypad, analog inputs, digital inputs, or over the
communications bus. A sleep mode shall be included in the PID functions. This feature shall allow the
motor to be stopped when at minimum speed for a user-defined period, for additional energy savings.
3. Two (2) programmable analog inputs shall accept a current or voltage.
4. Analog inputs shall include a filter to remove any oscillation in the input signal. The minimum and
maximum values (gain and offset) shall be adjustable within the range of 0 to 20 mA and 0 to 10
Volts. Additionally, the reference must be able to be scaled so that maximum reference can represent
a frequency less than 60 Hz, without lowering the drive maximum frequency below 60 Hz. Process
variables shall be capable of being inverted.
5. Six (6) programmable and isolated digital inputs for maximum flexibility in interfacing with external
devices. These inputs can also be used to activate the setpoints of individual control loops.
6. One (1) programmable analog output proportional to Frequency, Motor Speed, Output Voltage,
Output Current, Motor Torque, Motor Power (kW), DC Bus voltage, Active Reference, and other data.
Output will be selectable for 0 to 10 Vac or 4 to 20 mA.
7. Three (3) programmable digital relay outputs. The relays shall be rated for maximum switching
current 8 amps at 250 Vac, 8 amps at 24 Vdc and 0.4 A at 125 Vac. Two (2) outputs shall be Form C
and one (1) Form A. Open collector outputs are not acceptable.
8. Seven (7) programmable preset speeds.
9. Two (2) independently adjustable accel and decel ramps. These ramp times shall be adjustable from
1 to 3000 seconds.
10. The VFD shall be capable of catching a “spinning motor” In the forward or reversing direction
11. The VFD shall Ramp or Coast to a stop, as selected by the user.
12. The displayed operating information shall be user-defined and include up to nine (9) parameters
which can be viewed and monitored at one time.
13. All applicable operating values shall be displayed in engineering (user) units.
14. The keypad shall include a backlit LCD display. The display shall be in complete words for
programming and fault diagnostics.
15. The keypad shall utilize wizards to help navigate the HVAC application. These wizards will walk the
user through the steps required for PID set-up, Start-up, Multi-pump Mode and Fire-Mode.
16. The VFD shall include a fireman’s override input.
17. The VFD shall have the following protection circuits. The drive shall announce the fault condition in
full text on the keypad display, and shall display a HELP function which explains the possible cause
of the fault and the possible remedy. The protection circuits are:
a. Overcurrent
b. Overvoltage
c. Undervoltage
d. Unit over-temperature protection
e. Ground fault protection