Page 32
IronHorse GSD8 DC Drives User Manual – 1st Ed. Rev. A – 10/15/2019
Parameter Parameter Name
Description
GSD8-
240-5C
All other
GSD8
drives
16
S1/S2 Input Edge
and Prescaler
Configuration
This parameter determines how the GSD8-240-5C processes the S1 and
S2 signal input. It specifies which signal edge is used for measurements
and the value of the internal frequency dividers or prescalers. Modes with
prescalers greater than 1 should only be used if the input pulse rate on
S1 or S2 exceeds the unit’s maximum native pulse rate (see specifications
for details); otherwise, the control loop may become sluggish and
unnecessarily inaccurate. Use the following chart to configure this
parameter. As an example, assume an application requires input pulse
rates on S1 of 120,000 pulses-per-minute and S2 of 35,000 pulses-
per-minute. According to the electrical specifications, the unit can only
accept 50,000 pulses-per-minute on each of the S1 and S2 inputs. With
this in mind, the S1 and S2 prescalers should be selected as Falling/4
(120,000/4 = 30,000, below the 50,000 limit) and Rising/1 (no change
needed for S2). In this case, parameter 16 would be set to 2.
Selection Chart
S1 Input Edge and Prescaler
Rising/1 Falling/1 Falling/4 Falling/16
S2 Input
Edge and
Prescaler
Rising/1
0
1
2
3
Falling/1
4
5
6
7
Falling/4
8
9
10
11
Falling/16
12
13
14
15
See “Parameter 16 Encoder/Motor Assignment Table” on page 47 for
Parameter 16 values based on installed encoder PPR and motor RPM
ratings.
Power-up Target
Speed
This Parameter determines the default Running Value when power is
initially applied to the GSD8.
• Mode 1: Default to Zero
When in this mode, the unit will default to zero (engineering units).
• Mode 2: Default to Power-Up Value
When in this mode, the unit will default to the Power-up Value,
Parameter 17.
• Mode 3: Default to Previously Running Value
When in this mode, the unit will default to the previous running value
before power was removed. A previous running value must have
been active for at least 3 seconds to be recalled after power has been
disconnected and reapplied.
17
Power-up Value
When Power-up Mode is set to 2, this Parameter will designate the
default display value at power-up in the user’s desired units of measure
(“engineering units”), e.g. RPM, GPM, FPM, etc.
