SUBROUTINE TYPE53(TIME,XIN,OUT,T,DTDT,PAR,INFO,ICNTRL,*)
C***********************************************************************
C*    Copyright ASHRAE.  Toolkit for HVAC System Energy Calculations
C***********************************************************************
C*    SUBROUTINE:             MIXISIM
C*
C*    LANGUAGE:               FORTRAN 77
C*
C*    PURPOSE:                Calculate the mass flow rate of two
C*                            entering streams in a flow mixer with
C*                            the leaving mass flow rate and the
C*                            temperatures of all the streams known.
C***********************************************************************
C*    INPUT VARIABLES  DESCRIPTION(UNITS)                      SAMPLE VALUES
C*    XIN(1)  MLvg  Mass flow rate of mixed stream(kg/s)           3.65
C*    XIN(2)  TLvg  Temperature of mixed stream(C)                11.7147
C*    XIN(3) T1Ent  Entering temperature of stream 1(C)            1.67
C*    XIN(4) T2Ent  Entering temperature of stream 2(C)           23.89
C*
C*    OUTPUT VARIABLES
C*    OUT(1) M1Ent  Mass flow rate of stream 1(kg/s)               1.9999
C*    OUT(2) M2Ent  Mass flow rate of stream 2(kg/s)               1.65001
C*    OUT(3)ErrStat Error flag (0=ok, 1=error)(-)                  0.0
C***********************************************************************
C     MAJOR RESTRICTIONS:     Specific heats equal for two streams
C
C     DEVELOPER:              Shauna Gabel
C                             Michael J. Brandemuehl, PhD, PE
C                             University of Colorado at Boulder
C
C     DATE:                   January 1, 1992
C
C     INCLUDE FILES:          None
C     SUBROUTINES CALLED:     None
C     FUNCTIONS REQUIRED:     None
C
C     REVISION HISTORY:       None
C
C     REFERENCE:              None
C***********************************************************************
C     INTERNAL VARIABLES
C     deltaT        Temperature difference of entering streams       (C)
C     small         Small number used in place of zero
C***********************************************************************

      INTEGER Errstat, INFO, IOPT, NI, NP, ND
      DOUBLE PRECISION XIN, OUT
      DIMENSION XIN(4), OUT(3), INFO(15)
	CHARACTER*3 YCHECK(4), OCHECK(3)

      DATA small/1.E-9/
	DATA YCHECK/'MF2','TE1','TE1','TE1'/
	DATA OCHECK/'MF2','MF2','DM1'/

      MLVG  = XIN(1)
      TLVG  = XIN(2)
      T1ENT = XIN(3)
      T2ENT = XIN(4)

      ErrStat = 0
	IOPT	= -1
	NI		= 4		!CORRECT NUMBER OF INPUTS
	NP		= 0		!CORRECT NUMBER OF PARAMETERS
	ND		= 0		!CORRECT NUMBER OF DERIVATIVES

	IF(INFO(7).EQ.-1) THEN
		CALL TYPECK(IOPT,INFO,NI,NP,ND)
C	 CHECKS TO SEE IF USER'S INFO MATCHES CORRECT NUMBERS
		CALL RCHECK(INFO,YCHECK,OCHECK)
C	 CHECKS TO SEE IF INPUT AND OUTPUT UNITS MATCH
	ENDIF

      deltaT = T2Ent-T1Ent
      IF(ABS(deltaT).LT.small) deltaT=small

C1*** Calculate the mass flow rate of stream 1

      M1Ent = (T2Ent-TLvg)/deltaT * MLvg

C1*** Calculate the mass flow rate of stream 2

      M2Ent = MLvg-M1Ent

      OUT(1) = M1ENT
      OUT(2) = M2ENT
      OUT(3) = ERRSTAT
      RETURN 1
      END