Libraries
9.5 USS library
S7-200 SMART
554
System Manual, V2.3, 07/2017, A5E03822230-AF
9.5.2.4
USS_RPM_x instruction
Table 9- 31 USS_RPM_x instructions
LAD / FBD
STL
Description
CALL USS_RPM_W, XMIT_REQ, Drive,
Param, Index, DB_Ptr, Done, Er-
ror, Value
CALL USS_RPM_D, XMIT_REQ, Drive,
Param, Index, DB_Ptr, Done, Er-
ror, Value
CALL USS_RPM_R, XMIT_REQ, Drive,
Param, Index, DB_Ptr, Done, Er-
ror, Value
There are three read instructions for the USS protocol:
•
USS_RPM_W instruction reads an unsigned word
parameter.
•
USS_RPM_D instruction reads an unsigned double
word parameter.
•
USS_RPM_R instruction reads a floating-point
parameter.
•
Only one read (USS_RPM_x) or write
(USS_WPM_x) instruction can be active at a time.
The USS_RPM_x transactions complete when the drive acknowledges receipt of the
command or when an error condition is posted. The logic scan continues to execute while
this process awaits a response.
Table 9- 32 Valid operands for the USS_RPM_x instructions
Inputs/outputs
Data type
Operands
XMT_REQ
BOOL
I, Q, M, S, SM, T, C, V, L, Power Flow conditioned by a rising edge detection
element
Drive
BYTE
VB, IB, QB, MB, SB, SMB, LB, AC, *VD, *AC, *LD, Constant
Param, Index
WORD
VW, IW, QW, MW, SW, SMW, LW, T, C, AC, AIW, *VD, *AC, *LD, Constant
DB_Ptr
DWORD
&VB
Value
WORD
DWORD, REAL
VW, IW, QW, MW, SW, SMW, LW, T, C, AC, AQW, *VD, *AC, *LD
VD, ID, QD, MD, SD, SMD, LD, *VD, *AC, *LD
Done
BOOL
I, Q, M, S, SM, T, C, V, L
Error
BYTE
VB, IB, QB, MB, SB, SMB, LB, AC. *VD, *AC, *LD