Configuration Word (Pressure)

Default: 0x0000

Six bits of this 16-bit word control the configuration of the module. Bit 0 is the LSB; bit 15 is the MSB.

Bits 12 - 14 - Analog Input Type bits

These bits are used to select the type of analog input being used. Use the following table to select the appropriate input range:

Bit 14	Bit 13	Bit 12	Analog Input Type
0	0	0	Voltage: 0V to +10V
0	0	1	Voltage: -10V to +10V
0	1	0	Voltage: 0V to +5V
0	1	1	Voltage: -5V to +5V
1	0	0	Current: 4mA to 20mA

For a description of the corresponding transducer count ranges, refer to the Counts topic.

Bit 6 - Reverse Drive Mode bit

When this bit is set, the polarity of the axis’s output voltage is reversed. Notice that this only affects the analog axis’s output. Therefore, for auxiliary pressure or force axis only Open Loop commands are affected by this mode, and position/pressure control is not (recall that position/pressure control uses the drive output of the position axis). However, for pressure-only and force-only control axes, this will reverse the drive output when in Open Loop or pressure control.

This bit is only useful when you are connected to two drives which do not have differential or isolated inputs, and you need one to extend with positive drive and the other to extend with negative drive. (If the drives have differential or isolated inputs, you can just reverse the connections to the drive that must extend with negative drive.) When this bit is set, transducer counts will DECREASE with positive drive.

Warning: This bit must be set properly when the Set Parameters command is issued.

Bit 5 - Absolute Mode bit

Note: This bit is only available on pressure-only and force-only control axes and not on auxiliary pressure and force axes. You can still use absolute mode with auxiliary pressure and force axes, but the Absolute Mode bit of the position axis is used.

When this bit is set on a pressure-only or force-only axis, the drive output is limited between 0 and 10 volts. Therefore, if the drive would have gone negative it will be set to zero and the integrator will be cleared to avoid integrator windup. This is used in situations where either the pressure input is controlled by the RMC but the output is constantly bleeding out, or in situations where the RMC controls the output but the input is constant.

Bits 1 - 2 - Prescale Divisor bits

These bits are used to prescale (reduce the resolution of) the Counts. Use bits 1 and 2 as follows:

Counts ÷	Bit 2	Bit 1
1	0	0
2	0	1
4	1	0
8	1	1

For example, if bit 1 is set, but bit 2 is cleared, then the transducer counts will be divided by two before being processed. It is more desirable to use these bits to apply the same divide-by on the Scale factor; round off errors are minimized with the divide-by bits.

For example, suppose we calculate that our scale should be 2015.87, but because all parameters must be integers, we enter 2016. We have an error of 0.01%. However we could use a Prescale Divisor of 8 and a Scale of 16127 to give us an effective scale of 16127/8 or 2015.875. The error on our scale is reduced to 0.0002%.

Notice that for differential analog axes, this pre-scale divisor affects both Counts A and B.

Bit 0 - Integrator Limit

When this bit is cleared, the integrator limit is 20% of the maximum drive output. When the bit is set, the limit is 80%. If the integrator tries to go above the limit, the Integrator Windup bit in the Status word is set and the integrator value is held at the limit. The integrator limit is designed to prevent the drive output from saturating. This bit does not take affect until the axis is regulating the pressure because the integrator is not active while in position mode.